Non-Linear Editors: How To’s

There’s no magic wand waving when it comes to audio post production – The golden rule is to ‘get right at the source’, that is, try to record your source audio as best you can during the shoot. Sometimes though, different takes from different days need to be monkey-hooked together, or stock audio is needed, low budget ‘Foley‘ must be used, combined with found sounds such as from freesound.org, for that matter. For most of us re-recording is simply not an option and so we look to post production to clean, smooth and enhance our scene’s sonic landscape.

Everything

In Its Right Place

Don’t use a tonne of different plugins in any random order. Audio degrades rapidly when pushed and pulled to extremes, much more so than video. Under-process in post and you’ll discover that with just a few plugins in your chain you can fix messy audio very quickly.

Crop Your Audio

Your recording, sound effect, ADR or Foley can feel bloated when frequencies below 20Hz (imperceptible to the human ear) are left present in encoded audio information. Crop your audio inwards in order to expand what’s pleasant to your ears.

Insert an EQ on your audio channel, or set up your in built channel EQ

Cut all frequencies below 20Hz by engaging the ‘High Pass‘ control. During playback slowly sweep the control upwards to 100Hz.

Listen for a lighter sensation – a clarity in the audio due to it being less bloated, and stop. You might stop at 40Hz or even 60Hz.

If the sound is thin, pull the control back down towards 20Hz a little to reintroduce any welcome body or fullness. Find a sweet spot between these two points.

Know What You’re Dealing With: Use an Audio Analyzer

When the eye aids the ear you can be more sure of what doing, what you’re seeing aligns with what you’re feeling. What frequencies make your audio messy? What clicks and pops and handling noise occupy what sonic space? What constant average level do our special effects need to be at in order for us to properly mix them into our project?

Bringing an Audio Analyser into your project and applying it to both your master output and individual channels can be a real time saver. Insert the analyzer on your audio channel and during playback of your low quality clip or sequence watch the graphical display

Lead with your ears and follow with your eyes. When a certain harsh passage, a grainy sequence, a cracked moment, a rough, loud or distracting sound occurs try to catch it’s graphical movement.

Many Analysers have a ‘Freeze’ function. This button, once pressed, will freeze the graphical display in place and show you a snapshot of the frequencies present at that instance in time. You can then home in on the sound, even if it is brief, and correct it.

During playback very quickly click ‘freeze’ when you hear a distracting unpleasant sound. Now you have a snapshot of that particular moment. If you see a very sharp peak at 3,100Hz (3.1kHz) then this is your harsh, sheering metal grinding sound. If you see a large peak at 250Hz, this is your boxy, guttural, boomy sound.

The handy ‘Freeze’ function also renders the output level of that instant in time. Look at the output meters on the your Analyser to see how loud that particular phrase was, and also how intense that particular frequency was. With this information you can begin audio correction

Low / Low Mid / High Mid / High

It’s unlikely you’ll go into each waveform and individually EQ out each undesirable frequency by hand. In fact, this wouldn’t be advised as it would fall into the realms of over processing. Before you zone in on the most obvious clips, or offending parts of a longer waveform then the rule of thumb is often this: use broad, subtle sweeps and peaks to generalise and not scrutinise your audio correction. EQ across the entire audio channel (and not the individual clip) gives us this initial general remedy.

Insert a parametric EQ onto your audio channel or clip

Think of your audio in 4 quarters, rather than a whole. The first quarter being called ‘Low’, the second ‘Low-Mid’, the third ‘High-Mid’ and the fourth ‘High’

Don’t forget to apply the frequencies you discovered in the audio analysis here. The frequencies below are just examples to get your started:

Select a band and set a -3dB cut. e.g. Cut -3dB @ 60Hz to correct too much bass, bloated sub and muffled low end.

Select another band and set a -3dB cut @ 250Hz. This is where boomy, boxy, low roomecho resides, can bunch up and be problematic

Select a third band and set a -3dB cut @ 3,000Hz (3kHz) . This is where harsh, cutting, sharp sounds often become prominent

Finally set up your fourth band with a -3db cut @ 16,000Hz. Here the very high frequencies can sound hissy, digitally bright and burned

You might not need all four EQ bands engaged together. Use your ears and your audio analysis to select EQ bands to process

The last step is to use the output gain on the EQ plugin to give back what’s been taken away (in terms of level/volume). Set it from somewhere between +1.5dB and +3dB to replenish your reduced audio and in turn lift those pleasant frequencies that were not cut by EQ

Audio Correction: Attack the Clip

fix messy audio in your NLE

With some subtle Eq’ing now applied to your audio channel you can focus your attention on individual clips, sliced parts of sequences or how two clips in combination end up feel messy and dissonant. To successfully fix messy audio video editing techniques tend to parallel to audio techniques. Techniques such as deNoise, deClick, Noise Gate but also ambience, reverb, width control and other mastering tools can be used.

Here are a few techniques to fixing problem clips

Use the audio analyzer to home in on errors. Utilise the ‘freeze’ function, as mentioned earlier to get a snapshot of an instance of time when the problem sounds out. Use your eyes too, zoom into the waveform and look for sharp spikes and peaks – these are tell tale signs of overly dynamic sonic problems

If the audio clip is too dynamic (too loud and too quiet – inconsistent across time) then insert a compressor onto your clip. Set your compressor’s ‘attack’ to fast – somewhere from 0.01 to 0.30ms. Set your compressors ‘release’ to fast – somewhere from 10 to 50ms. Set your compressors ratio to 6:1 (for every 6dB going in the compressor will only let 1dB out). Set your output gain to +3dB. Now, whilst playing back, slowly reduce the ‘threshold’ control down from 0dB to -25dB. Watch the meters and listen for audio to ‘even out’. Quieter sounds are now closer in level to louder sounds

Surgically remove clicks and pops by zooming into your audio waveform and slicing offending sections out completely. It can be wise to use third party audio editing software such as Audacity, Sound Forge or Wavelab. Alternatively, if the clicks are too frequent, consider using dePop and deClick plugins that can mask and reduce clicking sounds

Noise gating can help to dynamically reduce the ambient room sound of an audio recording. Most noise gates are different from noise reduction in so much as they reduce level, as apposed to high frequency hiss and noise. Insert a noise gate plugin before EQ and before compression in order for the noise gate to work more effectively.

Encourage Experimentation

If you’re set on damage control and are determined to bring your recordings up to an improved quality then experimentation, as well as trial and error, is recommended. EQ and Compression are your main tools, while audio analyzers, noise reduction and noise gates are allied to those tools. For me, audio analyzers allow for a great amount of accuracy when pinpointing sonic deficiencies that are not obvious to the ear right away.

I hope this article brings you closer to fixing messy audio and lays out some of the tools that make approaching audio with analytical ears easier and more intuitive – Let us know how it works out for you!

Do you apply your audio effects to an audio clip or an audio channel? The answer is, of course, it depends entirely on what you’re trying to achieve. Special effects might be applied to certain scenes, certain clips – whereas more global tasks such as sweetening, enhancing and mastering ADR would require effects placed on an entire audio channel. In a word, audio channels give you consistent and coherent processing in post to help unify audio collected from different sources.

Audio Channels

Are the Top Down View

It’s true to say that preparing channels to better receive audio clips, no matter the source or content, is a vital time saver, and not only that, can be a quick fire way to ‘standardising’ a multitude of clips into one coherent sonic space – every sound is sat in one room, within the same four walls and not spread out over various psychoacoustic planes.

Set Up A Channel EQ Template

We use templates to save time but also to unify our workflow and create succession. The way we create is ‘our’ way, and over time we build strong methodology to that effect. EQ, being your forever-friend in post, can be used to very subtly clean, contour, polish and embellish within audio channels, not just individual clips.

Insert an EQ on your audio channel, or set up your in built channel EQ

Cut all frequencies below 20Hz and, depending on how your ears perceive the very low end of the audio source, cut everything below 50Hz. Do this by engaging the ‘High Pass’ control. The effect is an ‘unclogging’ creating a subtle openness especially in location recordings and environmental ambience.

Sound effects such as street noise, a crowd softly murmuring in a cafe, birds singing, distant thunder, the engine of a war class submarine – Each of these effects can benefit, with maybe the exception of the submarine, from having the ‘sub’ frequencies removed. As always, use your ears and become sensitive to sensation, as apposed to just experience.

Warmth, Tone And Punch

Warmth is a generic word for the fullness and body in audio sources. It’s logical to say that subtle warmth achieved across each audio channel will result in a warmer final mix. With EQ, we require a small ‘shelf‘ lift in the low frequencies that sit above the sub frequencies such as 80Hz to 180Hz. This is where the ‘body’ of a rapturous roll of thunder lies, this is the thickness in the ‘thud’ of a suicidal corpse or of a felled tree. Used subtly, and with care it can be applied across audio channels globally.

Engage a band in your EQ and set it to a ‘low shelf’. Between 80Hz and 180Hz. Your shelf should roll off, finishing around 200Hz.

With channel EQ, subtlety is key. Set your shelf EQ from between +1.5dB amd +3dB only.

For extra punch, you can add a ‘bell‘ boost in the low range from 60Hz to 100Hz. The ‘bell’ shape is a curve that centers around one particular frequency and is much more accurate that the long flat ‘shelf’ type EQ. Anything from +1dB to +6dB can improve on thin, porous sounding audio.

Be cautious when using strong, sharp ‘bell’ curves boosting frequencies on audio channels. Sharp boosting or cutting is a technique best used on individual audio clips on a case by case basis. Use broad, subtle lifting and cutting on audio channels.

Compression And Control

Compression is available as a built-in audio channel effect in most NLEs for a reason. The dynamic reduction of loud signals needs to be automated by compression, otherwise we would be lumbered with the arduous task of manually keying in level reduction as that tree fell, or thunder clapped across the shivering torpor. It’s worth mentioning at this point that the effect of compression is a sensation more than a sound. For example, 10 channels each with with heavy compression settings will ‘feel’ very different (almost suffocated) to channels where no compression is used. Apply compression when audio is dynamic – i.e. really quite to really loud in short bursts.

Insert a compressor before the EQ plugin on your audio channel, or engage the in-built channel compression

One benefit of the compressor is called ‘makeup gain’. It adds character to audio by lifting levels back up after compression reduction

Set your threshold using your ears. During playback slowly lower the threshold control until you hear the dynamics (freedom, airyness, openness) of the audio compress and reduce. The point is to bring loud sources under a general control, give them a character and a flavour. You’ll notice audio straight from a DSLR camera of an excitable football crowd feeling chaotic, out of control and too dynamic

Try to aim for no more than -3dB reduction on average. If you are compressing much more than this, then consider applying compression to individual clips on a case by case basis and not as a global channel effect.

Stereo Sound Stage

When mixing a number of audio sources together – street ambience, car horns, footsteps, weather sounds, dessert rain falling on corrugated cabins, the war cry a rogue interstellar mercenary, for example, it’s important to pay attention to the available sonic sound stage. Setting predefined pan positions can help to separate sounds, and the frequency spectrum they are comprised of allowing you to see and locate each before you begin EQ and compression. Will a cyclist moving at speed from left to right across a scene need panorama? With a stereo recording, no – that movement is embedded inside the stereo information of the audio recording. Foley, or mono sound replacement will need more care, and also creativity.

Here are a few techniques to experiment with panorama on your NLE audio channel

Set your pan control no more than 85 full left or 85 full right as extreme panning can sound very unnatural to the ear.

For sound sources with no apparent visual location, such as a bird chirping, a plane passing overheard, a fracas in some distant part of the city, pan can be set up randomly. Bear in mind, due to ‘panning law‘, audio can sound quieter and louder depending on it’s extreme panoramic position

By making a copy of your audio channel, effectively doubling your audio source, panning channel 1 to the left 85 and channel 2 to the right 85 and setting channel 1 to delay playback 20ms can create ‘Pseudo Stereo‘ effects. Although Pseudo Stereo can sound quite cheap compared to natural stereo when used very subtly, way back in a mix, it can be a colourful psychoacoustic ‘bed’ for a richer, more immersive sound stage.

Sounds don’t often move the way objects do. Panorama is about binaural psychoacoustic location and so, during playback, use your ears to place sounds in natural spaces, or use artistic license to bring believeablility to surreal, post-human soundscapes.

Workflow Wins

There’s a large emphasis placed on workflow in post and while setting up audio channel templates does address this, it should part of a larger, more personal methodology. Take away some or just one of these techniques and inter-lock them into your own daily practices to help streamline your NLE audio channel.

I hope this article helps you approach audio channels and audio clips differently, priming your project ready for audio post production… let us know how you get on!

It’s a well known fact that noise reduction introduces unwanted artifacts into your audio recording. The processing of dynamic high frequency analysis introduces freckles, glitches and that underwater effect across the high frequency spectrum. Not good.

Noise Reduction

Is a Remedy Not a Cure

The good news is that using noise reduction subtly and complimenting this process with EQ can bring noisy DSLR recordings back to life.

Use the ‘Learn’ Function

First off, all noise is different depending on the type of mic used in the recording, as well as it’s placement, the amount of gain applied and a number of other factors. Noise Reducers can come with a ‘learn’ function. ‘Learn’ analyses the nature of the noise attached to your audio and creates a ‘noise profile’, which makes for more accurate noise reduction.

Insert a Noise Reduction plugin on your audio channel or clip

Look for the ‘Learn’ function of the plugin and click it. Press play running your noisy audio through the plugin for some time. Analysis of the noise spectrum will begin and reduction will perform more efficiently now that your ‘noise profile’ has been made.

Play with the Threshold Control

Noise reduction works best when you constantly play your audio source through the plugin and reduce the ‘threshold’ down very slowly.

Listen not only for reduction of hiss and noise but also increases in unwanted artifacts. Find a balance between satisfactory reduction of noise and unwanted artifacts such as fractals, crackle and smear.

Don’t worry too much about audio sounding dull and underwater, this can be corrected later. However, reducing hiss will reduce clarity, sparkle and intelligibility so the key is to us the effect subtly. Find a balance between a natural sound and a reduction in hiss and noise.

Brighten and Recover

Now that you have reduced hiss and noise to a satisfactory level you’ll notice the source audio feeling dull and subdued, but only slightly. The subtle use of DeNoisers is key here, to avoid unwanted artifacts from effacing the audio. Using EQ, Compression and Gain can recover from this underwater effect. EQ is the tool you need at this stage.

Look to engage the ‘High Shelf’ normally located on the far right of the EQ. This will lift frequencies in the high range bringing clarity, brilliance and air back into the audio recording.

Select a frequency between 10,000Hz (10kHz) and 12,000Hz (12kHz)

Set the gain from between +3db and +6db

Set the output gain on your EQ plugin to +1.5dB

Zone In On the Sweet Spot

With all audio, no matter the source, there will be a sweet zone of frequencies in the high range that when subtly boosted will add sharpness and intelligibility. The human voice piques our interest at around the 1,000Hz (1kHz) range. Our ears have natural abilities at these frequencies, which is why we can often pick out distant human voices despite being smothered in external environmental sounds.

Set a frequency band control to 1000Hz (1khz)

Set it’s gain control to +6db

Slowly sweep the control from 1kHz to 9kHz listening carefully to your camera audio recording.

Find a spot where things pop out a little more but don’t re-introduce the noise you were experiencing.

Now reduce the gain of that EQ control from +6dB down to +3dB to settle on a subtle boost of the sweet spot

Perfection is Inhuman

It’s worth considering that recording perfectly crisp, clean, super-quiet audio is not possible for the majority of us, and nor is perfect audio always desirable. Some noise can add analogue character to a recording and noise reduction plugins can only go so far as to tame problem source audio. That said, noise issues are a common problem and the key is to use DeNoisers subtly, then compliment this transparent processing with EQ.

I hope this article is inspiring and helps you tame unwanted hiss and noise in your DSLR recordings.. let us know how you get on!